Intermittent disturbance combined N and P adding favor colony size and abundance of Microcystis flos-aquae

Abstract

Nutrients and disturbance are both important environmental factors in the freshwater ecosystem. Here we present data on the effects of intermittent disturbance (ID), nitrogen and phosphorus adding (+N+P), and intermittent disturbance combined N and P adding (ID+N+P) on colony size and abundance of Microcystis flos-aquae in lab experiments. Results showed that the mean colony sizes of M. flos-aquae in ID+N+P group were1.68, 1.56, 1.17 times that in the control, +N+P, ID groups, respectively. Moreover, the average number of M. flos-aquae in ID+N+P group were 1.47, 1.19, 1.42 times those in the control, +N+P, ID groups, respectively. The average concentration of EPS (extracellular polysaccharides) in ID and ID+N+P group was significantly higher than those in control and +N+P groups. Results demonstrated that intermittent disturbance combined N and P adding promoted colony size and abundance of M. flos-aquae. These results suggest that intermittent disturbance combined N and P adding plays an important role in the formation of Microcystis blooms in freshwater ecosystems.